1. Technical Field
The present invention relates to a read head reading coded data by optical scanning.
2. Related Art
Japanese Unexamined Patent Application Publication No. 2003-30580 and Japanese Unexamined Patent Application Publication No. 2004-199266 disclose a barcode reader which allows a movable mirror to reflect a laser beam emitted from a light emitting element, swings the movable mirror to apply the laser beam to a target (barcode), allows the movable mirror to reflect a return beam from the target, and allows a light receiving element to receive the return beam.
However, since the barcode readers disclosed in Patent Documents 1 and 2 both have a movable mirror, which can be swung, separately from the light emitting element and the light receiving element, it is difficult to reduce the cost and the size.
Since the light emitting element and the light receiving element are generally fixed to a fixed section, the movable range of the mirror may be narrowed depending on the position relation relative to the mirror and thus the readable range of the barcode reader may be easily limited.
When a barcode is generated by holography, the barcode can be recorded in a multiplexing manner (angle-multiplexed recording or wavelength-multiplexed recording), thereby greatly enhancing the capacity of the barcode.
However, a barcode reader (read head) for reading data such as a barcode multiply recorded by holography did not exist in the past.